Children missing events have been drawing social concerns. When a child and his guardian wander away from each other, in the prior art, for example the child may send a short message to or initiate a voice call with the guardian by dialing the guardian's phone to advise the guardian of his current position information. However, it is very difficult to clearly describe the current position information as not being familiar with the ambient surrounding; furthermore, assume the child is confronted with a wicked abductor due to insufficient security awareness, he hardly finds his guardian. The guardian can only resort to news media or government authority to search the child, but the person search effectiveness is undesirable.
Hence, it is urgently desirable to provide a method of ensuring the guardian aware of the child's safety information at any time.